A review of physical growth in children and adolescents with Autism Spectrum Disorder

• An overall growth dysregulation exists in infancy and early childhood in ASD.
• Longitudinal studies of growth in older children and adolescents with ASD are needed.
• There may be subgroups within ASD characterized by growth parameters and ASD severity.
• Future work should investigate the biological underpinnings of growth dysregulation.
• HPA axis dysfunction or connective tissue abnormalities may adversely affect growth.

Head circumference growth in individuals with an Autism Spectrum Disorder (ASD) has been well characterized in the first two to three years of life and reflects a period of acceleration followed by a period of deceleration when compared with their typically developing (TD) peers. While this altered growth trajectory has been consistently found for head circumference, it is less clear if an abnormal growth trajectory also exists across measures of height and weight. Moreover, most studies have focused on infancy and early childhood, and no longitudinal data have been collected in older children with ASD. This review focuses on the physical growth trajectory of individuals with ASD, and proposes that a general growth dysregulation is present in ASD, and that an endophenotype within ASD may exist that is characteristic of extreme overgrowth. Two possible explanations for a general growth dysregulation are suggested: (1) a connective tissue disorder, which is frequently associated with increased height and disproportionate body ratios; and (2) a dysregulation of the hypothalamic–pituitary–adrenal (HPA) axis, which regulates growth hormones. The existence of a general growth dysregulation, and possible endophenotype, may serve as a potential biological marker in ASD.